From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 72ACFF30950 for ; Thu, 5 Mar 2026 11:56:25 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DD32F6B00AB; Thu, 5 Mar 2026 06:56:24 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id D9B286B00AD; Thu, 5 Mar 2026 06:56:24 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C96456B00AE; Thu, 5 Mar 2026 06:56:24 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id B99186B00AB for ; Thu, 5 Mar 2026 06:56:24 -0500 (EST) Received: from smtpin30.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 6534A1A0949 for ; Thu, 5 Mar 2026 11:56:24 +0000 (UTC) X-FDA: 84511856688.30.EDB7EB0 Received: from out-188.mta0.migadu.com (out-188.mta0.migadu.com [91.218.175.188]) by imf16.hostedemail.com (Postfix) with ESMTP id A9F20180008 for ; Thu, 5 Mar 2026 11:56:22 +0000 (UTC) Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=FxYOARU5; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf16.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.188 as permitted sender) smtp.mailfrom=qi.zheng@linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1772711782; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=8hyqbb8F2NRNHHFp77Ms/+jViunOCmw3TEFzht4PTD4=; b=YUYGTc3A9jGjDgRXwvbB23iiBt1Ch8uug6zj3T0xzNojPIvq0aoJOvlsc6kykctMTy+6vL P41XiD8S0Gm0Otgh4tg/65FTHn0JxdxuajlOExuydgBUaA9knmcX9hwH5FLuzvVCHRd+j2 524/kWaKcGRr8ETk5G9OHIOg1xSDIhc= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1772711782; a=rsa-sha256; cv=none; b=nF7zmtffO2RMHJrAqeWyJXHa+00KiV9ZBDDpFQ7QaAFI6qMJZqdnqIahipZ+a4hmpFzPbb 35pEInDXTRXWnSnVF+2D0HG9BKZHZQ1Sr2fpe+g+Kr3Ytdv6i9flolitdf5opzOIwPNltr FKzHjcGa6fNSD2RnEcu+BVOGcfnF4/E= ARC-Authentication-Results: i=1; imf16.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=FxYOARU5; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf16.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.188 as permitted sender) smtp.mailfrom=qi.zheng@linux.dev X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1772711780; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=8hyqbb8F2NRNHHFp77Ms/+jViunOCmw3TEFzht4PTD4=; b=FxYOARU5x0g+Zna+Ay1ysDbQ1ntMsGhY8lLL89aloYuqaM4oNBrujP2pa/q0wx6LwQTaci fEFYT5Sp4lq00AepmhrB0Hut0n4GXtU8qSaP1MKimCke1uJOslo9LqbnfjQJFz5e6dfAeb K7bYbN5wfpK5v5eB3OUoXcoLkaNQKDE= From: Qi Zheng To: hannes@cmpxchg.org, hughd@google.com, mhocko@suse.com, roman.gushchin@linux.dev, shakeel.butt@linux.dev, muchun.song@linux.dev, david@kernel.org, lorenzo.stoakes@oracle.com, ziy@nvidia.com, harry.yoo@oracle.com, yosry.ahmed@linux.dev, imran.f.khan@oracle.com, kamalesh.babulal@oracle.com, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, chenridong@huaweicloud.com, mkoutny@suse.com, akpm@linux-foundation.org, hamzamahfooz@linux.microsoft.com, apais@linux.microsoft.com, lance.yang@linux.dev, bhe@redhat.com, usamaarif642@gmail.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Muchun Song , Qi Zheng Subject: [PATCH v6 13/33] mm: migrate: prevent memory cgroup release in folio_migrate_mapping() Date: Thu, 5 Mar 2026 19:52:31 +0800 Message-ID: <0f156c2f1188f256855617953f8305f43e066065.1772711148.git.zhengqi.arch@bytedance.com> In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: A9F20180008 X-Stat-Signature: oo1otiq97jigkfmi4xo6y1nm18k3w6zu X-Rspam-User: X-HE-Tag: 1772711782-587344 X-HE-Meta: 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 WtDcag3R 37BF0UU8Sx7+8JXWYzv3B3IBl1DOwoWi7KTci86XrtRjt6BYvuAC3eiTAoazE3lmpOVUm/wZVz0JNJe0YcjX+4bjSPhoA4+8fhWgvMH84/A6NBglPXgjapSKhAmWQCBAlnSA4Qm59XdCYKdV0QXgZcZUFzx5JNEGFSVqVw32QMrAFJVAZGb97tuDiAbtkVRCbL9rXp6sQat7rR+Fvp4j6xnZ/xQqcOUMfn2nWBvyvDcpP6rV2aplVdgNLzpVfxC+QJQpODlKNw58Pp0VcrAcVYoSCLePICrNCj/wSyo3Rlx4NOo/25MadRO+Zr8B0hHSoHkpL Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Muchun Song In the near future, a folio will no longer pin its corresponding memory cgroup. To ensure safety, it will only be appropriate to hold the rcu read lock or acquire a reference to the memory cgroup returned by folio_memcg(), thereby preventing it from being released. In __folio_migrate_mapping(), the rcu read lock is employed to safeguard against the release of the memory cgroup in folio_migrate_mapping(). This serves as a preparatory measure for the reparenting of the LRU pages. Signed-off-by: Muchun Song Signed-off-by: Qi Zheng Reviewed-by: Harry Yoo Acked-by: Johannes Weiner Acked-by: Shakeel Butt --- mm/migrate.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/migrate.c b/mm/migrate.c index 6cc654858da65..27e6103037c29 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -672,6 +672,7 @@ static int __folio_migrate_mapping(struct address_space *mapping, struct lruvec *old_lruvec, *new_lruvec; struct mem_cgroup *memcg; + rcu_read_lock(); memcg = folio_memcg(folio); old_lruvec = mem_cgroup_lruvec(memcg, oldzone->zone_pgdat); new_lruvec = mem_cgroup_lruvec(memcg, newzone->zone_pgdat); @@ -699,6 +700,7 @@ static int __folio_migrate_mapping(struct address_space *mapping, mod_lruvec_state(new_lruvec, NR_FILE_DIRTY, nr); __mod_zone_page_state(newzone, NR_ZONE_WRITE_PENDING, nr); } + rcu_read_unlock(); } local_irq_enable(); -- 2.20.1